#include <sys/cdefs.h>
#include <sys/types.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>

#include <limits.h>
#define	NCHARS	(UCHAR_MAX + 1)		/* Number of possible characters. */
#define	OOBCH	(UCHAR_MAX + 1)		/* Out of band character value. */

#include "tr.h"

static int map1[NCHARS] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* ASCII */
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14,
		0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
		0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c,
		0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
		0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44,
		0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50,
		0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c,
		0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
		0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74,
		0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80,
		0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c,
		0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
		0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,
		0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0,
		0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc,
		0xbd, 0xbe, 0xbf, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8,
		0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4,
		0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0,
		0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec,
		0xed, 0xee, 0xef, 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
		0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, }, map2[NCHARS];

static void setup(int *, char *, char *);
static void myputchar(char);
static int mygetchar(void);

/*
 * tr -ds string1 string2
 * Delete all characters in string1.
 * Squeeze all characters in string2.
 */
void tr_ds(set1, set2)
	char* set1;char* set2; {
	int lastch, ch;

	setup(map1, set1, 0);
	setup(map2, set2, 0);

	for (lastch = OOBCH; (ch = mygetchar()) != EOF;)
		if (!map1[ch] && (!map2[ch] || lastch != ch)) {
			lastch = ch;
			myputchar(ch);
		}
}

/*
 * tr -d string1
 * Delete all characters in string1.
 */
void tr_d(set1)
	char* set1; {
	int ch;

	setup(map1, set1, 0);

	while ((ch = mygetchar()) != EOF)
		if (!map1[ch])
			myputchar(ch);
}

/*
 * tr -s string1
 * Squeeze all characters in string1.
 */
void tr_s1(set1)
	char* set1; {
	int lastch, ch;

	setup(map1, set1, 0);

	for (lastch = OOBCH; (ch = mygetchar()) != EOF;)
		if (!map1[ch] || lastch != ch) {
			lastch = ch;
			myputchar(ch);
		}
}

/*
 * tr [-s] string1 string2
 * Replace all characters in string1 with
 * the character in the same position in string2.  If the -s option is
 * specified, squeeze all the characters in string2.
 */
void tr_s2(set1, set2)
	char* set1;char* set2; {
	int lastch, ch;

	if (!*set2)
		errx(1, "empty set2");

	/* If string2 runs out of characters, use the last one specified. */
	setup(map1, set1, set2);

	setup(map2, set2, 0);

	for (lastch = OOBCH; (ch = mygetchar()) != EOF;) {
		ch = map1[ch];
		if (!map2[ch] || lastch != ch) {
			lastch = ch;
			myputchar(ch);
		}
	}
}

void tr(set1, set2)
	char* set1;char* set2; {
	int ch;

	if (!*set2)
		errx(1, "empty set2");

	/* If string2 runs out of characters, use the last one specified. */
	setup(map1, set1, set2);

	while ((ch = mygetchar()) != EOF)
		myputchar(map1[ch]);
}

static void setup(map, set1, set2)
	int *map;char *set1;char *set2; {
	char lastch;

	if (!set1)
		assert(0);

	if (!set2) {
		memset(map, 0, NCHARS * sizeof(int));
		while (*set1)
			map[(unsigned char) *set1++] = 1;
		return;
	}

	// set2 not empty => translate	
	while (*set1 && *set2)
		map[(unsigned char) *set1++] = *set2++;

	// set1 longer that set2 => use last set2 char till set1's end
	lastch = *(set2 - 1);
	while (*set1)
		map[(unsigned char) *set1++] = lastch;
}

static void myputchar(ch)
	char ch; {
	if (putchar(ch) == EOF)
		errx(1, "error writing to stdout");
}

static int mygetchar() {
	int ch;
	if ((ch = getchar()) == EOF && ferror(stdin))
		errx(1, "error reading from stdin");
	return ch;
}
